Parents of young children may notice that as their child's ability to talk increases, so do the number of questions a child asks. And when parents are a little preoccupied, they may tire of answering questions but ScienceDaily.com says research conducted by the University of Michigan a few years ago found that "children are motivated by a desire for explanation."
In one study, researchers studied typical conversations that children from ages 2 to 4 had with family members and visitors at home. In another, they followed conversations that children ages 3 to 5 had in a laboratory. The studies used small numbers of children so they cannot be used to predict the behavior of all children but they did highlight interesting things about the way children try to get information.
Overall "…the researchers found that children seem to be more satisfied when they receive an explanatory answer than when they do not." The children's response to an explanation was to agree or ask a follow-up question. When they didn't get an explanation, the tended to repeat their question or give an "alternative explanation."
The researchers found that young children really do "want to get to the bottom of things" and they are not simply talking to keep the conversation going. While a tired parent may not see the difference between a child repeating the same question or asking a new one, the latter response may indicate that the child is satisfied with the initial answer but still want to know more.
One writer responded to this research on a Washington Post blog: "At first blush, this seems utterly self-evident, but I think back on the "why"-based conversations that I've had, and it felt like most of them weren't about information-seeking."
You may not be able to provide answers that prevent your child from saying "Why?" repeatedly but you may be able to think more patiently about these conversations if you know that your child is using his or her limited vocabulary to seek answers about the world.